Remove an unused PassRefPtr ctor

third_party/WebKit/Source/wtf/PassRefPtr.h

Index: third_party/WebKit/Source/wtf/PassRefPtr.h
diff --git a/third_party/WebKit/Source/wtf/PassRefPtr.h b/third_party/WebKit/Source/wtf/PassRefPtr.h
index af2a5a5a3f7fa2a308888b4d188d4b44c6ccd20b..c5c5165279787edf949c7fe87b0183c12b82011f 100644
--- a/third_party/WebKit/Source/wtf/PassRefPtr.h
+++ b/third_party/WebKit/Source/wtf/PassRefPtr.h
@@ -64,7 +64,6 @@ public:
     PassRefPtr() : m_ptr(nullptr) {}
     PassRefPtr(std::nullptr_t) : m_ptr(nullptr) {}
     PassRefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); }
-    explicit PassRefPtr(T& ptr) : m_ptr(&ptr) { m_ptr->ref(); }
     // It somewhat breaks the type system to allow transfer of ownership out of
     // a const PassRefPtr. However, it makes it much easier to work with
     // PassRefPtr temporaries, and we don't have a need to use real const